R Kelly

O.K. so I get engines a bit, I used to run saw, and sell firewood. I also performed golf course work for many years, and even went to Agg. school where we took a small engine course, all before, I was injured, but it got me back into hobbies pretty hardcore n I like it. I just saw a cartoon image of sorts that shows a basic gardem hose attached to a spigget w a nozzle at the end, one of the kinda pointy tipped old scool ones that turn left or right and it turns from a stream at high volume to a mist in a cone shape. So it says the Analogy is that he reffers H.S.N. to the spigget ie influx of volume, and the nozzle to the L.S.N. where basically the atomization is taking effect. Would anyone see any real validitu in this mode of interpretation or visualisation. cant post it found out how and I appearently need a certain # of posts before putting links in sorry

hustler777

iTrader: (1)

Ya that's about right....on most carb the high speed needle is just used to meter the volume of fuel entering the carb and the low speed needle does most of the work...I know on my alpha 872 all I touch is my high speed needle, and never more than an hour either way and I'm at full race tune....it took awhile to get used to this long needle style of carb, but once I got it figured out ill never go back to a short needle style carb

R Kelly

I found that this morning, and most information that I have come across was saying that the LSN was responsible for the bottom half of carb slide. While the HSN is responsible for the top half.so I have been staying away from HSN, bit at 1mm I cant get enough fuel to fire, I need to open the carb up w my trim and slowly close it as she warms. Seems like possibly if I open the HSN I may get more fuel pushing through the 1mm to fire and be closer to getting my Idle nailed in conjunction w my LSN, I have never touched my HSN yet for the reason I stated that I was under impression not to touch it till I was actually using the top half of the throttle, sorry for the novel

Boinker

That would be true up until about half throttle or 3/4 depending on the carburator in question. After the low speed needle leaves the spray bar the flow of fuel is dependent on engine vacuum, fuel tank pressure and of course the H.S.N. setting. Now if you have a mid-range... If you do leave it at factory. then that actually moves the spray bar out further into the barrel or closer to the back edge of the carb base. But other then that the analogy you gave is very accurate to a point.

As far as adjusting both needles remember that if you are tuning you have to start with the top end needle as it affects everything across the board. Get your engine up to temperature and start adjusting the high end until you have an acceptable amout of smoke, a good top end and the mid-range does not bog. One way to test the midrange is to go forward at about 1/4- 1/2 throttle then nail it. if you bog you are rich on the top and if you chock you are too lean. after that set the low end. What you are looking for is a respectable idle and it being able to idle for at least 5 seconds and then take off with very little to no lag.

After that set your idle screw. all engines will idle kind of high and then drop down. you want to set where the drop down is. IF you are actually at one mm opening then you may just need to tinker with the tune and the idle may end up right where it needs to be. if its too high and stays high , with the low end is set properly, turn it down 2 hrs and drive around for a minute. after that rinse and repeat until its where it needs to be.

IF you are new to this then it may be a good idea to have a temperature gun handy. once you learn to tune by ear then you will not need it but for now being new you may want to use it. And in addition to that I would read Houstons tuning bible to get the full spectrum of things.

hustler777

iTrader: (1)

Ya the tuning bible should be printed and included with every motor no doubt!!!

Just try and forget about the phrase top end needle and know it a fuel volume regulator, as it controls the amount of fuel that can enter the carb no matter the throttle position. By the time your done tuning, you should be perfect until the lowside needle leaves the carb body, after that you should be just a slight hair rich, and I do mean slight, as the most stress on the motor happens at high rpms, you'll want that hair bit more fuel/oil in the crank case

R Kelly

Now that this is starting to focus on me and my actuall problem,and if u could not tell I am GREEN AT NITRO but, I know chainsaws, and other things about the way engines work. I am no mechanic though. I need to open my carb up w my trim to like plus 22 to fire it right up u can get it to like say 16 almost immediatly then as it warms it starts to speed up I drop it down get down toreally almost zero really, no real blue smoke at idle but def when pull throttle unburnt fuel too, more just as I recently richened it w lowspeed to try to get more blue smoke to protectengine, if it stallls i need to crank carb open to fire just no pop even if warm it will start to poop at like plus 8 or 10 n fire at 12 or 14 and u can drop it quick cause it is warm. my real question is when carb is at zero can I open HSN get more fuel thru carb n get it to fire with out having to open carb w trim soo much.

beidle99

iTrader: (9)

Stop messing with your trim to get the engine to idle. Set it to 0 or what ever makes your horn 90* at the servo. You need to adjust idle with the idle stop screw and LSN needle.

you won't see much smoke at idle. Unburnt fuel is good if you are breaking in the engine as long as it is getting up to 220* and not more and no less then 190*

alexrckid

more good stuff..........
http://www.rchobbies.org/cars_eng-tuning.htm

alexrckid

and..........
http://www.rchobbies.org/engine-tuning.htm

hustler777

iTrader: (1)

What motor are you running?

alexrckid

i know why you're asking....seems he's got some basic setup problems....any of which can be resolved but knowing the make of the engine helps, for sure....

R Kelly

NvIsion >21 Race NVB 521R

R Kelly

NvIsion .21 Race NVB 521 R